Small rework of optimal vs maxsols

I wanted to make the "optimal" and "maxsolutions" options mutually
exclusive, but in the end I decided there is value in keeping both
(e.g. for specifying a limit to the number of solutions when asking
for "all" optimal").

Now optimal cannot be negative anymore, for the same reason of maxsolutions.

The interface user (shell, UI) will have to take care of handling this
in a way that makes sense for the user. Usually this means setting
the maximum number of solutions to UINT_MAX (or a similar very high
number) when the user wants "all optimal".

1 files changed, 12 insertions, 4 deletions

diff --git a/cpp/nissy.cpp b/cpp/nissy.cpp
index 944944b..92b10bd 100644
--- a/cpp/nissy.cpp
+++ b/cpp/nissy.cpp
@@ -21,8 +21,8 @@ extern "C" {
         long long nissy_gendata(const char *, unsigned long long, char *);
         long long nissy_checkdata(unsigned long long, const char *);
         long long nissy_solve(const char *, const char *, unsigned, unsigned,
-            unsigned, unsigned, int, int, unsigned long long, const char *,
-            unsigned, char *, long long *);
+            unsigned, unsigned, unsigned, unsigned, unsigned long long,
+            const char *, unsigned, char *, long long *);
         long long nissy_countmoves(const char *);
         long long nissy_setlogger(void (*)(const char *, void *), void *);
 }
@@ -182,11 +182,19 @@ namespace nissy {
 
         solver::solve_result
         solver::solve(const cube& cube, nissflag niss, unsigned minmoves,
-            unsigned maxmoves, unsigned maxsols, int optimal, int threads)
+            unsigned maxmoves, unsigned maxsols, unsigned optimal,
+            unsigned threads)
         {
+                solver::solve_result result;
+
+                if (maxsols == 0) {
+                        result.solutions = {};
+                        result.err = error::OK;
+                        return result;
+                }
+
                 const size_t len = 3 * (maxmoves+1) * maxsols;
                 std::vector<char> csols(len);
-                solver::solve_result result;
 
                 auto err = nissy_solve(cube.to_string().c_str(),
                     name.c_str(), niss.value, minmoves, maxmoves, maxsols,